acetic anhydride; triethylamine in dichloromethane T=20°C; 2 h;

hydrogenchloride Ambient temperature;

oxygen; methylene blue in acetone T=15 - 20°C; 177 h; Irradiation;

1: 1,8-naphthalaldehydic acid; WangBromo resin With chlorosulphonyl isocyanate; N-ethyl-N,N-diisopropylamine in N,N-dimethyl-formamide T=20°C; 18 h; 2: methanol With sodium methylate in tetrahydrofuran

1: 53 percent / LiAl(O-t-Bu)3H / tetrahydrofuran / 1.5 h / Ambient temperature 2: 95 percent / HCl / Ambient temperature View Scheme